The effect of orthodontic tooth movement on the human pulpal blood flow

本研究的目的是用激光多普勒血流仪(LDF)检测压迫力对牙髓血流量的影响。对参与者(年龄：24-31岁)的重要左上中门牙进行测量。短期(约20秒)侵入力(app.500gf)涂于被检查牙齿的切缘，并在距牙周边缘约2 mm处测量PBF，并在被检查牙齿上涂上不透明的黑色橡胶膜。在7名受试者中，有6名受试者在用力过程中观察到LDF流量信号的减少，但这种减少在统计学上没有显著意义。正畸托槽用4-Meta树脂粘接在被检牙和上颌第一磨牙的唇面上。在牙龈边缘切线2 mm处粘接一根不锈钢管，确保测量探头的准确导向。一种改良的实用弓(0.016*0.022英寸)与托槽接合，并被激活以对被检查的牙齿施加持续的侵入力(约50gf)。在施加侵入力前、施加过程中和施加后重复测量PBF。此外，对被检查的牙齿施加短期(20秒)手动控制的侵入力(50gf、100gf、200gf)，并记录PBF。持续的侵入力使PBF在施力过程中显著降低。短期施加侵入力对PBF的影响不受持续施加侵扰力的影响。实验结果表明，在正畸治疗过程中，施加压力会导致牙髓血流量的下降，监测牙髓血流量可以反映牙髓血流动力学的变化。

The purpose of the present study was to examine the effect of intrusive force application on the pulp blood flow (PBF) using laser Doppler flowmeter (LDF). Measurements were made in vital upper left central incisors of the participants (age : 24-31). Short-term (approx. 20 seconds) intrusive force (app. 500 gf) was applied to the incisal edge of the examined teeth, and PBF measurements were made at approximately 2 mm to the gingival margin with opaque black rubber dam application to the examined teeth. In 6 out of 7 subjects, reduction of the LDF flux signal during the force application was observed, however, the reduction was not statistically significant. Orthodontic brackets were adhered to the labial surface of the examined tooth and upper first molars using 4-META resin. A stainless steel tube was cemented at 2 mm incisal to the gingival margin securing an exact guidance for the measurement probe. A modified utility arch (0.016 * 0.022 inch) was engaged to the brackets and activated to exert continuous intrusive force (approximately 50 gf) to the examined tooth. PBF was repeatedly measured before, during and after the intrusive force application. In addition, short-term (20 seconds) manually-controlled intrusive force (50 gf, 100 gf, 200 gf) was applied to the examined tooth and PBF was also recorded. Continuous intrusive force produced significant reduction of PBF during the force application. The reduction of PBF produced by the short term intrusive force application was not effected by the continuous intrusive force application. Results obtained suggest that the intrusive force application produces reduction of PBF and that monitoring of PBF indicates the change of the pulpal haemodynamics during Orthodontic treatment.